Religious leaders are slamming a documentary to be shown at the nation's premier 9/11 museum because it might make people believe Islam was responsible for the attacks that killed nearly 3,000 people.

Already the lone imam on an interfaith advisory group to the National September 11 Memorial Museum has quit in protest at the seven-minute documentary.

"Unsophisticated visitors who do not understand the difference between al-Qaida and Muslims may come away with a prejudiced view of Islam, leading to antagonism and even confrontation toward Muslim believers near the site," Sheikh Mostafa Elazabawy, the imam of Masjid Manhattan, wrote in a letter to the museum director.

But the museum stands by the film, narrated by NBC News anchor Brian Williams. "We have a very heavy responsibility to be true to the facts, to be objective, and in no way smear an entire religion when we are talking about a terrorist group," Joseph Daniels, president of the nonprofit foundation that is overseeing the museum, told The New York Times.

The film, "The Rise of Al Qaeda," seeks to explain the historical roots of the 2001 attacks on the World Trade Center and Pentagon, reports the Times. It will be shown to visitors in a part of the museum next to a gallery with photographs of the 19 men who hijacked four planes.

"The screening of this film in its present state would greatly offend our local Muslim believers, as well as any foreign Muslim visitor to the museum," wrote Elazabawy, who resigned from the advisory board in March.

The film calls the terrorists Islamists who viewed their deadly mission as a jihad — and it is those two terms that have upset the advisory board. It also shows images of terrorist training camps and al-Qaida attacks spanning several years. The terrorists' beliefs are explained by people with foreign accents.

"The terrorists need to be condemned and remembered for what they did," Ahmed said. "But when you associate their religion with what they did, then you are automatically including, by association, one and a half billion people who had nothing to do with these actions and who ultimately the U.S. would not want to unnecessarily alienate."

But Daniels said the film has been thoroughly vetted, and refuses to make alterations to it. "What helps me sleep at night is I believe that the average visitor who comes through this museum will in no way leave this museum with the belief that the religion of Islam is responsible for what happened on 9/11," he said.

The museum's planners have been struggling for some time over how to represent Islam.

Peter Gudaitis, chief executive of New York Disaster Interfaith Services, said the museum rejected some suggestions from a panel of lower Manhattan clergy members who performed recovery work after the attacks. But there has always been agreement that the museum would make it clear that Muslims were among the attack's victims, mourners, and recovery workers.

On Monday, Gudaitis and another panel member, the Rev. Chloe Breyer, executive director of the Interfaith Center of New York, sent museum directors a letter to ask for edits to the film, saying they are concerned after experiences they had with anti-Muslim sentiment.

The museum, which will be beneath the World Trade Center plaza, is set to open on May 21.